成長於非極化氮化鎵之寬能隙材料及光電元件研究---子計畫一：非極性氮化鎵半導體材料元件磊晶成長

Abstract

非極性氮化鎵半導體由於在成長方向上不具內建電場，因此在能帶結構上具平帶特 性可使電子、電洞波函數在空間中重合比率高，因此在理論上發光效率可以比傳統具極 性之發光元件還來得高，故在利用其製作高效率發光元件上極具潛力。此外由於非極性 三五氮化物具相當強的偏振光特性，故在光性應用上十分廣泛。本計畫主要目的為成長 高品質的非極性相關材料及元件。利用有機金屬氣相沈積系統成長非極性發光二極體並 以降低縲旋差排及疊差密度為首要目標，主要利用之技術如利用磊晶側向成長技術、同 步成長氮化矽奈米結構層於磊晶層、調整適當之磊晶參數，以增加元件之發光性能，並 製作出偏光效率良好之元件。另外在製程方面，計劃運用了基板圖案化及表面粗化之技 術來提升元件之光萃取效率。再者，結合元件特性模擬及結構設計，我們可以運用DBR 結構於非極性面射型雷射之共振腔結構中，進而量測、分析非極性面射型雷射之高效能 元件及物理特性。

Unlike conventional c-plane devices, nonpolar nitride-base III-V semiconductor materials are free of polarization related electric fields along the growth direction. In theory, the emission efficiency of nonpolar devices would be better than that of c-plane devices. In addition, due to the anisotropic structure, nonpolar devices have much potential in optical applications. Epitaxial growth method of devices related to non-polar GaN with high quality was proposed in this project. With the goal of achieving the low threading dislocations and stacking faults density, the high efficient non-polar light emitting diodes would be grown by Metal-Organic Chemical-Vapor Deposition (MOCVD). Main techniques include epitaxially lateral over growth, in situ SiNx interlayer, and suitable epitaxial parameters. For process, pattern sapphire and surface roughness would be proposed to improve light extraction efficiency. Furthermore, to combine with simulation of characteristics and design of structure, distributed Bragger reflector (DBR) structure could be used to application of non-polar vertical cavity surface emitting laser (VCSEL). The high efficient performances and physical characteristics of non-polar VCSEL would be measured and identified.